Wire guide for grid making machine



Aug. 6, 1963 o. H. SCHADE, sR

WIRE GUIDE FOR GRID MAKING MACHINE 2 Sheets-Sheet 1 Filed Oct. 7, 1959 n .R M m m 7 mm A mm? B S H WA UWW Au 6, 1963 o. H. SCHADE, SR

WIRE GUIDE FOR GRID MAKING MACHINE 2 Sheets-Sheet 2 Filed Oct. 7, 1959 INVENTOR. UTTD H.5UHADE, SR.

Arram/EY United States Patent Filed Oct. 7, 1959, Ser. No. 844,932 3 Claims. (Cl. Mil-71.5)

This invention relates to apparatus for making wirewound grids for electron tubes and particularly to the Wire guide nose cone of such apparatus.

In the fabrication of one form of wire-wound grids, a plurality of side rod wires are first laid down longitudinally along a cylindrical mandrel of a grid lathe and then a lateral wire is wound therearound in a plurality of helical turns. In the grid lathe for winding such grids, the side rod wires are fed from supply spools and guided onto the mandrel through slots in an elongated wire guide nose cone. According to prior art design, the slots are disposed in radial planes uniformly spaced around said nose cone and converge toward the blunt tip thereof. The nose cone contains a central bore through which the mandrel is fed. The tip of the cone is encircled by a metal ring which encloses the otherwise opened slots and thus forms an array of rectangular passageways through which the wires are fed.

In such prior art design the width of the slots ideally should be equal to the diameter of the side rod wires. This equality would prevent lateral movement of the wires in the slots and thus insure uniform circumferential spacing of the side rods. However, in practice the slots are wider than the diameter of the side rod wires in order to prevent clogging by dust or metal dirt particles. For small grids such dirt particles are often of appreciable size compared to the side rod wires themselves. These wider slots permit excessive lateral movement of the side rods within the slots. This is especially noticeable with grids having a large number, e.g., 45 to 70 fine side rods each of which is one mil or less in diameter. Accordingly, difficulty has been encountered in obtaining accurate uniformity of spacing between side rods. This in turn creates a number of problems in subsequent tube fabrication as well as undesirable electrical characteristics of the tube made with the grid, and also undesirable variations from tube to tube in the electrical characteristics.

It is therefore an object of my invention to provide a grid winding lathe having an improved slotted wire guide nose cone in which dirt does not cause harmful clogging and yet which is capable of guiding a plurality of side rod wires into a cylindrical array in very accurate uniform circumferential spacing. According to my invention the wire guide nose cone includes a tubular tip having therein a plurality of relatively large slots, equally circumferentially spaced. These slots extend back along the tip from its end. The slots are askew with respect to the central axis of the tubular tip, i.c., the axes of each slot and of the tubular tip are non-parallel and non-intersecting.

In the drawings:

FIG. 1 is a side elevation partly in section of a part of a grid winding machine incorporating my invention;

FIG. 2 is an enlarged side elevation partly in section of the wire guide nose cone made according to my invention; and

FIG. 3 is an end view of the wire guide nose cone made according to my invention illustrating the operative disposition of a side rod wire therein.

In FIG. 1 a part of a grid winding apparatus 1t includes a frame 12 on which a rotatable lead screw 14 and a rotatable winding head 16 are mounted. A carriage 18 is supported on the lead screw 14 and is adapted 3,100,005 Patented Aug. 6, 1963 to be moved therealong in response to a rotation of the lead screw. Motor and drive means (not shown) are provided for rotating the lead screw 14. A mandrel 20 suitable for fabricating a grid thereon is mounted on the carriage 14.

The winding head 16 includes a support bushing 22 in which a wire guide nose cone 24 made according to my invention is mounted. The support bushing 22 and wire guide nose cone 24 are provided with aligned central bores through which the mandrel 20 may be advanced for a grid winding operation.

In the fabricating of a grid, side rod wires 26 are fed from a plurality of supply reels 27, through guide tubes 28, and then through slots in the nose cone 24, and onto the mandrel 20. A lateral wire 29 is wound around and upon the side rod wires 26 on the mandrel 20 from a lateral wire supply reel 30. The lateral wire supply reel 36 is supported on an annular rotating disk 32 through which the mandrel 20 is advanced. The rotating disk 32 is rotated by motor and drive means (not shown).

An enlarged detail of the wire guide nose cone 24 according to my invention is shown in FIG. 2. The nose cone 24 comprises a tubular member 40 having at one end thereof a wire guide cylindrical tip section 42 and at the other end a slightly tapered frusto-conical section 43 for receipt by the support block 22. A plurality of rectangular slots 44 are provided in the cylindrical tip 42 and extend from the free end thereof back along the tip 42 askew with respect to the central axis 45 of the tip. A slot 44 may also be defined as angled relative to a radial plane containing an end of the slot. Such angle is indicated as or in FIG. 2 where the slot axis 46 intersects the radial plane normal to the paper at the end of its slot 44'. The angle on may also be defined as the angle between the projections onto the plane of the paper in FIG. 2 of the central axis 45 and of the axis 46 of the slot 44', the slot 44 being that one whose projected end lies on the nose cone axis 45. The angle a for each slot may be quite small, e.g., 2 to 8. However, as will become apparent from the following description the angle on is not critical and may be more or less as desired.

The slots 44 may be cut progressively by a small diameter cutter moved along the desired angle, or they may be cut 1n a single plunge cut by a disk cutter having a large radius R such that the depth of the slots 44 are a maximum at the free end of the tip 42 and taper to zero at some distance removed from the end.

The cylindrical tip 42 of the nose cone 24 is stepped arhacent the end thereof so that a draw ring 47 may be fitted therearound and thus for-m the end portions of the open slots 44 into an array of rectangular passageways as shown in FIG. 3.

In the grid Winding apparatus 10 of FIG. 1, the side rod supply reels 27 and guide tubes 28 are so disposed relative to the slots 44 that the side rod wires 26 enter the Slots 44 substantially parallel therewith. However, when the side rod wires 26 emerge from the slots 44 from] under the draw ring 47, they are pulled axially and parallel to each other Ialong the mandrel 20 by the advance of the mandrel. Such pulling action serves to pull the side rod wires firmly against the side walls of the slots and thus prevent any lateral movement of the side rod Wires in the slots. Such disposition of the side rod wires 26 in the slots 44 is made possible by the angled disposition of the slots 44 according to my invention.

It will thus be appreciated that uniformity of circumferential spacing of the side rods wires 26 as laid down on the mandrel 20 is independent of the width of the slots. Rather, uniformity of side rod spacing is dependent only upon the uniformity of spacing of the slots 44 around the nose cone 24. Because of the complete independence 3 of side rod spacing uniformity with respect to slot Width, the slots 44- can be made sufliciently large to avoid any possibility of clogging due to dirt particles.

Although angled guide slots may be incorporated on nose cones without :an end cylindrical section 42, such a cylindrical section provides a very desirable advantage. Regardless of the material of which the nose cone is made, continuous rubbing of the side rod wires 26 over the front edges of the slots 44 will cause these edges to wear away. If different slots wear away different amounts, the uniformity of side rod spacing provided by the slots would be affected. However, since the end of the nose cone is cylindrical, the end surface thereof may be ground away to restore the uniformity of spacing between the side walls of adjacent slots without afiecting the relationship between the guide slots 44 and the mandrel 20.

What is claimed is:

1. A grid windingmachine comprising means for supporting an elongated cylindrical mandrel, means for moving said mandrel support means for axially advancing said mandrel, side rod wire guide means having a bore therethrough for receiving said mandrel, said side rod wire guide means including a tubular tip having a plurality of slots therein for feeding side rod wires to said mandrel, said slots being substantially Wider than the diameter of said rod wires along the entire length of said slots, and said slots being circumferentially spaced around said tip and extending from the end thereof back along said tip, the axis of each slot being non-parallel and nonintersecting respect to the axis of said bore therein, means for feeding side rod wires through said slots and along the respective axes of said slots while said wires are in said slots and for pulling said wires along said mandrel in a direction parallel to the mandrel axis after said wires have left said slots, and means for winding a lateral wire around said mandrel and the side rods therealong, whereby said side rod wires extend parallel to each other and to said mandrel.

2. A grid winding machine comprising means for supporting an elongalted cylindrical mandrel, means for moving said mandrel support means for axially advancing said mandrel, side rod wire guide means having a bore therethrough for receiving said mandrel, said guide means including a tubular tip having a plurality of slots therein for feeding side rod wires to said mandrel, said slots being substantially wider than the diameter of said side rod wires along the entire length of said slots, and said slots being circumferentially spaced around said tip and extending from the end thereof back along said tip, the projection of each of the axes of said slots and the projection of the axis of said hore on a plane tangent to said tubular tip at an end of each of said slots making an acute angle with respect to each other, means for feeding side rod wires through said slots and along the respective axes of said slots while said wires are in said slots and for pulling said wires along said mandrel in a direction parallel to the mandrel axis after said wires :have left said slots, and means for winding a lateral wire around said mandrel and the side rode wires therealong.

3. A grid winding machine comprising means for supporting an elongated cylindrical mandrel, means for moving said mandrel support means for axially advancing said mandrel, side rod wire guide means having a bore therethrough for receiving said mandrel, said side rod guide means including a tubular tip having a plurality of slots therein through which side rod wires are fed to said mandrel, said slots being substantially wider than the diameter of said side rod wires along the entire length of said slots, and said slots being circumferentially spaced around said tubular tip and extending from the end thereof back along said tip, the projection of each of the 'axes of said slots and the projection of the axis of said bore on a plane tangent to said tubular tip at an end of each of said slots making an acute angle with respect to each other, means for feeding said Wires through said slots and along the respective axes of said slots while said wires are in said slots and for pulling said wires along said mandrel in a direction parallel to the mandrel axis after said wires have left said slots, whereby said side rods are arranged in an accurately uniformly spaced cylindrical array, and means for winding a lateral wire around said side rod wires along said mandrel.

References Cited in the file of this patent UNITED STATES PATENTS 6,082 Roebling Feb. 6, 1849 1,526,148 Hoovens Feb. 10, 1925 1,592,909 Sleeper July 20, 1926 2,136,388 Lowe Nov. 15, 1938 2,216,189 Ennis Oct. 1, 1940 2,719,544 Hinnann Oct. 4, 1955 2,725,901 Bngel Dec. 6, 1955 FOREIGN PATENTS 471,323 France July 8, 1914 

1. A GRID WINDING MACHINE COMPRISING MEANS FOR SUPPORTING AN ELONGATED CYLINDRICAL MANDREL, MEANS FOR MOVING SAID MANDREL SUPPORT MEANS FOR AXIALLY ADVANCING SAID MANDREL, SIDE ROD WIRE GUIDE MEANS HAVING A BORE THERETHROUGH FOR RECEIVING SAID MANDREL, SAID SIDE ROD WIRE GUIDE MEANS INCLUDING A TUBULAR TIP HAVING A PLURALITY OF SLOTS THEREIN FOR FEEDING SIDE ROD WIRES TO SAID MANDREL, SAID SLOTS BEING SUBSTANTIALLY WIDER THAN THE DIAMETER OF SAID ROD WIRES ALONG THE ENTIRE LENGTH OF SAID SLOTS, AND SAID SLOTS BEING CIRCUMFERENTIALLY SPACED AROUND SAID TIP AND EXTENDING FROM THE END THEREOF BACK ALONG SAID TIP, THE AXIS OF EACH SLOT BEING NON-PARALLEL AND NONINTERSECTING WITH RESPECT TO THE AXIS OF SAID BORE THEREIN, MEANS FOR FEEDING SIDE ROD WIRES THROUGH SAID SLOTS AND ALONG THE RESPECTIVE AXES OF SAID SLOTS WHILE SAID WIRES ARE IN SAID SLOTS AND FOR PULLING SAID WIRES ALONG SAID MANDREL IN A DIRECTION PARALLEL TO THE MANDREL AXIS AFTER SAID WIRES HAVE LEFT SAID SLOTS, AND MEANS FOR WINDING A LATERAL WIRE AROUND SAID MANDREL AND THE SIDE RODS THEREALONG, WHEREBY SAID SIDE ROD WIRES EXTEND PARALLEL TO EACH OTHER AND TO SAID MANDREL. 